Yoon, I.J. and Hong, J.-W., 2017. Safety equipment for swimming beaches in Korea: Implications for management. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 1–5. Coconut Creek (Florida), ISSN 0749-0208.

Since December 2014, the Act on the Use and Management of Swimming Beaches of Korea has imposed safety requirements on swimming beaches. Of 314 surveyed beaches in Korea, only 6% met current national lifeboat requirements, while 24% met rescue boat requirements, 61%, life belt; 69%, watch tower; 67%, swimming area buoy; and 84%, safety buoy or warning notice requirements. This study recommends a classification system for beaches based on congestion and administrative capabilities. Based on this system, safety equipment requirements were revised. Recommendations included exempting extra-small and small-scale beaches from watch tower and rescue boat requirements and equipping medium-large beaches with an additional rescue boat.

Chang, J.-I. and Yoon, S., 2017. Assessing the economic value of beach restoration: Case of Song-do Beach, Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 6–10. Coconut Creek (Florida), ISSN 0749-0208.

In 1913, Song-do beach in Busan was declared the first official public beach in Korea. However, since the 1990s, erosion levels have increased and in 2003, Typhoon Maemi caused extensive damage to the beach and coastal road. It has taken several public restoration projects to restore the capacity of recreation and coastal protection. This study aims to analyze the economic benefits of the Song-do beach restoration by verifying benefit factors of the coastal erosion control and beach restoration, such as recreational services and various coastal ecosystem services. We applied a non-market valuation method, contingent valuation method, which allows the measuring of individual willingness to pay for the beach restoration project. The annual economic value of the restoration is estimated at 2,542 KRW (2.5 USD) per household and its total economic benefit is about 234.7 billion KRW (229.8 million USD). These findings have key implications for policymakers with quantitative information and decision makers related to beach restoration policies.

Kang, D.Y.; Hong, S., and Lee, J., 2017. An introduction of AELIS (Aquatic Environment Life-saving Integrated System). In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 11–15. Coconut Creek (Florida), ISSN 0749-0208.

AELIS (Aquatic Environment Life-saving Integrated System) is designed to monitor the high profiles of drowning and the swimmers approaching the swimming boundary lines in real time in order to prevent accidents in the water environment and maintain high standard of the safety. It also detects the swimmers who attempt to get in the water without lifeguards at night, which has high possibility of drowning. The system automatically recognize the potential danger in the blind spots where lifeguards hardly manage. AELIS proactively reduces the risk of life-threatening accidents and supports fast rescue by paging to the lifeguards and safety officers of the facilities. AELIS utilizes an image perception algorithm to detect violation of swimming boundaries and keep tracking of swimmers during its operation. The system is developed based on intelligent video surveillance algorithm, the CCTV, and Geographical Information System (GIS), which enables real time warning to the safety operators in the aquatic environment.

Lee, M.S.; Chun, S.B.; Park, C.; Suh, K.B., and Lee, C.W., 2017. Perception of safety as a mediator in the relations among service quality, satisfaction, and behavioral intention at Korean beach sites. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 16–20. Coconut Creek (Florida), ISSN 0749-0208.

This research verifies the mediating effect of perception of beach safety on the relationship among beach service quality, customer satisfaction, and behavioral intention. A questionnaire was used for measurement. Convenience sampling of Non-probability sampling was used. Three hundred and five questionnaires were distributed in the Seoul and Gyeong-gi areas, of which 295 were used for the final analysis to evaluate the hypotheses. SPSS 21 and AMOS 20.0 software were used to conduct the frequency analysis, validity tests, confirmatory factor analysis, correlation analysis, and structural equation modeling analysis. The results were as follows. First, beach service quality was found to have a significant relationship with customer satisfaction. Second, customer satisfaction was found to be significantly related to revisiting behavioral intention. Third, the beachgoer's perception of safety was found to have a mediating effect between customer satisfaction and behavioral intention.

Shin, E.H.; Kang, D.Y., and Lee, J., 2017. Analysis and international comparison of drowning in South Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 21–25. Coconut Creek (Florida), ISSN 0749-0208.

From WHO (World Health Organization), drowning is the third leading cause of accidental death in the world. The number of drowning around the world is collected from the lifesaving organizations through ILS (International Lifesaving Federation) based on the statistics office in the nations. The cause of death is categorized by international and/or national code of disease and most of nations comply with the codes however some of LMICs (Low Middle Income Country) manually count the drowning by accidents reported in the newspapers. After Sewolho ferry wreck in 2014, which brought about 300 drowning in South Korea, more attention has been drawn to water safety but there has been no statistical data in accordance with international guideline in South Korea. Korean Coast Guard and National Emergency Management Agency make annual report of drowning accidents, which states that the annual drowning is about 30 but it is far away from the actual number around 700 drownings from National Statistics Office in South Korea. This study is designed to provide realistic numbers of drwonings to establish national water safety and drowning prevention strategy. Numbers of drowning from 2008 to 2012 is collected from National Statics Office based on KCD (Korea Classification of Disease) and it is analysed by gender, age, place and etc. Also the characteristics of drowning accidents is compared to the international ones.

Kim, K.B.; Lee, J.H.; Kim, S.G.; Seok, K.H., and Choi, Y.S., 2017. Improvement plan on marine lifesaving educational course in Korea: Comparison with the status of the foreign marine leisure safety education groups. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 26–29. Coconut Creek (Florida), ISSN 0749-0208.

The objective of this study is to identify the current status of qualification system of life guard in Korea and to suggest objective developmental plans according to domestic circumstances through qualification systems in Japan, Canada, and Finland. It is required to provide reliable education system by unifying the life-guard education courses in each education provider. The Life-guard educationl based on locational and environmental factors should be more sub-divided and standardized in advanced programs in the same manner as life-guard education system in member countries of ILS. Korea is recommended to authorize ILS certificates and unify certificate standards that can be comparable with acquisition of international mobility. The Education for life-guard and issuance of certificate shall be advanced and classified in details according to spatial, geographical, and environmental elements, and the education program should establish the policies as a world class standard.

Kim, H.M.; Kang, D.Y.; Kim, T., and Lee, J., 2017. Analysis of the awareness change of public CPR training in metropolitan Seoul from 2011 to 2015. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 30–34. Coconut Creek (Florida), ISSN 0749-0208.

Cardiopulmonary Resuscitation (CPR) is the first response for a drowning victim. The quick action of lifeguards and facility operators is crucial to elevate the survival rate. However, there are plenty of beaches and waterfronts without lifeguards; therefore, bystander CPR is equally as important. To increase bystander CPR, public education is essential. This study analyzes the changing perceptions of CPR training and the change in people's confidence in executing CPR after a public CPR education program in metropolitan Seoul from 2011 to 2015. The participants were public school students, teachers, social workers, and public staff who reside in metropolitan Seoul. Between 2011 and 2015, 205,949 people participated in a public CPR training program organized by Lifesaving Society Korea. After each 2–4 hour-long training, course operators collected a questionnaire. Researchers separated the collected results into two categories-program type and training format- and from there further separated the results. In the program type (hours) category, researchers used the following delineations: (1) 2-hour long adult CPR and AED (Automated External Defibrillator); (2) 3-hour adult, pediatric, and infant CPR and airway obstruction; (3) 3-hour adult CPR, AED, and airway obstruction; and (4) 4-hour adult, pediatric, and infant CPR, AED, and airway obstruction. The training format category was further broken up as follows: (1) alternating explanations of skills with practice and (2) full lecture followed by practice. Compared to 2011, which is regarded as the beginning of the public CPR training movement an increasing number of participants responded that they have participated in CPR training before and that they had confidence in their ability to execute CPR. Most participants preferred a small class size class-no more than 20 participants- some participants described the benefits of using simple words rather than medical terminology. There is no significant difference in satisfaction with different instructors. Periodic recertification and public CPR awareness programs contribute positively to CPR execution confidence and willingness to perform CPR in everyday life. Therefore, this study concludes that public CPR programs should be expanded to more schools, work places, and public facilities. In addition, public CPR training programs need to better explain first aid. Using this study's results, training policies-such as recertification period, training format, and hours- can be modified to improve the programs' effectiveness.

Jeong, Y.M.; Kim, S.G.; Lee, J.H.; Yoon, J.S., and Lee, W.D., 2017. Understanding characteristics of upward and downward flows in coral reef region for safety of recreational diving. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 35–39. Coconut Creek (Florida), ISSN 0749-0208.

The goal of this study is to gain an understanding of the flow characteristics in reef regions through numerical simulations for safe recreational diving in the region. The applied numerical model was first validated to verify its feasibility and validity for carrying out the numerical simulations. Subsequently, an underwater survey was conducted in the Visayan Islands in the Philippines to model the reef region. Based on the underwater survey results, simulations were conducted in a three dimensional numerical wave tank with a model coral island. According to the numerical analysis results, stronger currents were generated if either currents or both currents and waves entered the low water level lagoon area of the coral island. In addition, an overall trend of stronger flow velocities was observed when both waves and currents were present than when only currents were present. Particularly strong upward and downward flows and strong vortices were generated near the reef crest. Thus, open water divers who are inexperienced in underwater swimming need to pay particular attention when swimming in these areas. Lastly, six tips for safe diving in reef regions were obtained from analysis of the numerical results.

Nakashita, S.; Nakamoto, K.; Koshikawa, Y.; Kim, K.-H., and Hibino, T., 2017. Evaluation of granulated coal ash as artificial seabed for eelgrass. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 40–44. Coconut Creek (Florida), ISSN 0749-0208.

Granulated coal ash (GCA) is a by-product of coal-fired thermoelectric power stations. In this study, GCA was used to create a functional artificial seabed for eelgrass. Moreover, the capability of GCA for the growth of eelgrass in an indoor experiment was examined to elucidate the ability of eelgrass to establish itself and grow in a GCA artificial seabed created in an actual marine environment. The eelgrass in the GCA artificial seabed branched and adapted similar to that on sandy ground. A stable eelgrass community was established in one year in an actual marine environment. Furthermore, five years after transplantation, the eelgrass community was maintained. For the GCA artificial seabed, the oxidation–reduction potential of the bottom sediments was approximately 100 mV higher than that of the surrounding ground, and the amount of sulfide decreased to approximately one third of that of the surrounding ground. Even five years after construction, a stable environment was preserved. Therefore, it is concluded that GCA is an effective material for an eelgrass seabed.

Lee, Y.-G. and Jang, A., 2017. Measurement of lead in seawater using gold nanoparticles modified screen-printed carbon electrode. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 45–49. Coconut Creek (Florida), ISSN 0749-0208.

Due to their low detection limits, various types of spectrometry techniques have been used for determining lead [Pb(II)] in water. However, these methods are not applicable for the on-site measurements of Pb(II) since the equipment is too bulky and skilled laboratory staff are needed. In this study, coastal water samples were collected from different sites close to two coastal industrial complexes in Korea. Their Pb(II) concentrations were determined using electrodeposited gold nanoparticles (AuNPs) on a disposable screen-printed carbon electrode. Square wave anodic stripping voltammetry was used to enhance the sensitivity of the Pb(II) detection level with less than 5 μg/L. The square wave anodic stripping voltammetric response for high sensitivity was 0.018 μA/μg/L, the Pb(II) concentration range was 2 to 500 μg/L at the deposition time of 180 s, and the detection limit was 4.4 μg/L with good selectivity. These results indicate that there was no significant difference between our sensor and the conventional spectrometry method in precision and accuracy. The AuNPs based sensor demonstrated long-term stability for up to 7 days while being used in the continuous monitoring of 100 μg/L Pb(II) in seawater. An RSD value of 2.7% was obtained, and the sensor retained 93% of its initial activity after 7 days.

Han, J.-Y.; Lee, J.; Lee, Y.-G., and Jang, A., 2017. Solid-state ion selective lab chip sensor for on-site measurement of orthophosphate in small volumes of liquid. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 50–54. Coconut Creek (Florida), ISSN 0749-0208.

This paper described the characterization of the assembled solid-state ion-selective lab chip sensor to potentiometrically measure phosphate ion. Since the assembled chip sensor is easy to setup and does not require any sample preparations, it is an ideal technique to study the measurement of phosphate in small volumes of liquids or in estuarine sediments. The size of the proposed lab chip is 12 mm × 21 mm, and the microfluidic channel has the width of 2 mm, length of 5 mm, and depth of 150 μm. All electrodes have the length of 500 μm, width of 200 μm, and spacing of 200 μm. The potential response of the assembled phosphate ion-selective lab chip sensor showed a linear regression in the range of 1×10⁻⁵ to 1×10⁻³ M with a slope of 54 mV/decade. In addition, the experimental results showed a good precision, indicating that relative standard deviation (RSD) was 3.5%.

Kim, S.; Park, K., and Yang, B.-M., 2017. Validating the applicability of MACCS2 on the assessment of radionuclide deposition over the ocean in Fukushima Daiichi nuclear power plant accident case. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 55–59. Coconut Creek (Florida), ISSN 0749-0208.

On 11 March 2011, an enormous earthquake and tsunami occurred and caused a severe nuclear accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in Japan. Following the FDNPP accident, a significant amount of radionuclides were released into the environment. The radionuclides were released into the ocean by direct emission in liquid form or by atmospheric deposition onto the sea surface. According to the 2013 UNSCEAR report, atmospheric deposition of radionuclides significantly contributed to the contamination of the ocean, as did direct emission. The MELCOR Accident Consequence Code System 2 (MACCS2) is a code for estimating the off-site accident consequences of atmospheric radiological releases; the code utilizes the straight-line Gaussian plume model. In this study, to judge the code's applicability for estimating the radionuclide deposition over the sea surface in the Fukushima accident case, we conducted a comparative analysis of the MACCS2 results against previously published data. The long-range dispersion patterns from the MACCS2 calculation have a tendency simply to broaden from those of the short distance from the FDNPP. From the analysis detailed in this paper, we concluded that MACCS2 is applicable only for short-range dispersion (a few tens of kilometers) from an accident site, not for long-range dispersion as in the case of the Fukushima accident. The atmospheric deposition of radionuclides is a major cause of oceanic contamination; a large percentage of released radionuclides are deposited at long range from the accident site. Therefore, we suggest that any simulation code for atmospheric dispersion and deposition over the ocean should be based on another model, such as a Lagrangian or puff model, instead of on the Gaussian plume model, especially for long-range dispersion assessment.

Kim, K.-J. and Jang, A., 2017. The fouling characteristics of NOMs on the microfiltration ceramic membrane. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 60–64. Coconut Creek (Florida), ISSN 0749-0208.

The filtration performance and fouling characteristics of mixed natural organic matters (NOMs) on monolith ceramic microfiltration (MF) membrane was investigated in a dead-end mode under constant transmembrane pressure (TMP) with periodic backwash. Humic acid (HA), bovine serum albumin (BSA), and sodium alginate (SA) were used for the investigation of the fouling potential. In a pilot-scale filtration test, the fouling characteristics of NOMs were evaluated by the various operation conditions, including solution pH, foulant mixture, and rate of flux recovery. The NOMs and mixed NOMs caused severe permeability reduction, and the fouling potential varied significantly with diverse pH conditions (5.0, and 7.0). Acidic condition improved the membrane performance but generally resulted in more severe physically irreversible fouling than the neutral condition. The fouling characteristics of NOMs such as fouling rate and cake growth rate were offset after filtration in the MF ceramic membrane. The membrane fouling and cake growth rate of NOMs decreased in the order of BSA>SA>HA at pH 5.0 and SA>BSA>HA at pH 7.0. The results indicated that pH and mixed organic compounds had the greater impact on the degree of relative fouling characteristics such as reversible fouling (RF) and irreversible fouling (IF) as well as on the fouling rate in MF ceramic membrane.

Lee, E.-J.; An, A.K., and Kim, H.-S., 2017. Effects of coagulant with different basicity on membrane-based biological treatment for removing phosphorus. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 65–69. Coconut Creek (Florida), ISSN 0749-0208.

With growing concerns about water resource or environmental issues such as eutrophication and algae blooms, regulation about water quality of effluent has been reinforced in wastewater treatment plants. Membrane bioreactor (MBR), integration of membrane and biological processes, is regarded as alternative method due to its high quality of effluent. Coagulants are often added into a bioreactor to comply with the rigid standard of phosphorus. Addition of a lot of coagulants have potential adverse effects on MBR performance such as membrane fouling and low removal efficiency. Therefore, this study attempted to investigate the impact on microorganism or membrane permeability when polyaluminium chloride (PAC) was added for phosphorus removal. In batch test, addition of PAC with lower basicity interfered with biological decomposition of organic matters. When the selected PAC with the highest basicity (71%) was employed in continuous MBR, the process showed stable TMP and high-quality treated water due to no negative effect on microorganism.

Jung, H.R. and Kim, K.H., 2017. Monitoring of expansion and withering of Salix subfragilis communities in Namgang Dam reservoir. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 70–74. Coconut Creek (Florida), ISSN 0749-0208.

The water depth of Namgang Dam Reservoir is shallow and the water level fluctuation is relatively small, because it is located in a midstream plain of the Nam River. These conditions of Namgang Dam led to the growth of Salix subfragilis communities. Initially, they were distributed over small areas but over time, they rapidly proliferated to cover large areas. They generate large amounts of leaf debris particularly in the dry season, so that water quality could be deteriorated. And, in the flood season, they raise water levels by obstructing the water flow in tributary streams, this consequently leads to flooding damages. In addition, Salix subfragilis periodically undergoes self-thinning and the withered trunks and branches turn into driftwood. These problems pose difficulties to dam management. By the way, these communities began to wither in areas lower than the highest water level, after a long-term period of inundation in 2012. To determine the reason for the withering phenomena in this study, the relationship between water level(turbidity) and the withering of Salix subfragilis in dam reservoir was investigated, and the withering characteristics of Salix subfragilis communities were analyzed through aerial photographys and field surveys. Results of this study show that disruption of photosynthesis due to high turbidity during the long-term inundation is what was caused their withering.

Kim, G.-Y.; Jeong, J.-W.; Kim, M.-G.; Kim, H.-S.; Kim, J.-H., and Kim, H.-S., 2017. A study on scale determination of FO-RO hybrid process based on FO recovery rate. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 75–79. Coconut Creek (Florida), ISSN 0749-0208.

Recent studies have been actively conducted on forward osmosis-reverse osmosis hybrid process combining seawater desalination and wastewater reuse technology. It uses seawater as draw solution and reclaimed wastewater as feed solution in the FO process. Although it is possible to save operating costs in forward osmosis-reverse osmosis hybrid process, organic matter contained in treated water of forward osmosis may have a negative effect on the coastal environment. Therefore, studies are needed to evaluate the removal efficiency of organic matter in forward osmosis process and to enable the commercialization of forward osmosis process. Furthermore, the forward osmosis-reverse osmosis hybrid process is a region-specific technology because most wastewater treatment plants and seawater desalination facilities are not constructed together yet. Mass balance has not been considered in full scale plants. In this study, we determined material balance of forward osmosis-reverse osmosis hybrid process based on recovery rate of forward osmosis membranes, and estimated the scale. The results indicated that the recovery rate of the reverse osmosis process could be increased to 69.44% in case of 3 vessels connected in a series. The amount of wastewater that must be treated by the forward osmosis process was approximately 16,735 m³/day, indicating that mass balance can be set. In addition, the reverse osmosis and forward osmosis processes can be configured through simulations.

Min, B.-I.; Suh, K.-S., and Park, K., 2017. Analysis of continuing cesium release to the sea from the Fukushima Dai-ichi nuclear power plant until 2013. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 80–84. Coconut Creek (Florida), ISSN 0749-0208.

A two year time-series of ¹³⁷Cs concentration is presented from the ocean surface observed at sites 20 km radius from Fukushima Daiichi Nuclear Power Plant (FDNPP). The data used in this study were publicly released by the Tokyo Electric Power Company (TEPCO) and are available on websites of TEPCO. Publicly released data on ¹³⁷Cs radioactivity in seawater near the power plant strongly suggest a continuing release of radionuclides to the sea. The ¹³⁷Cs radioactivity in the harbour water was substantially higher than that of seawater outside and remained relatively stable after June 2011. The consistent gradient of radioactivity between observed results at outer sea sites a 20 km radius from FDNPP indicates that radionuclides are still being released continuously from somewhere in the vicinity of the reactor housings. The relatively stable ¹³⁷Cs radioactivity of the harbour water cannot be explained without a continuous input of radioactivity into the harbour. Assuming a steady state, there is a continuous input to the harbour and hence a continuous release to the outer sea.

Suh, K.-S.; Kim, S., and Min, B.-I., 2017. Atmospheric dispersion and sea surface deposition of radionuclides by the Fukushima nuclear accident. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 85–88. Coconut Creek (Florida), ISSN 0749-0208.

A large amount of radioactive material was released to the atmosphere and to the sea by the Fukushima nuclear accident in 2011. Most of the radioactive materials released into the air were moved to the Pacific Ocean due to the westerly jet stream, and some of them dispersed on land in Japan and were deposited in the area northwest of the Fukushima Daiichi power plant. A lot of radionuclides transported to the Pacific Ocean were deposited on the sea surface by a dry/wet deposition process, seawater and seabed sediments along the coastline of Fukushima Prefecture were contaminated. All of this deposition occurred in the early phase of the accident from March 11 to March 25 before the direct discharge into the sea on March 26. In this study, a three-dimensional atmospheric dispersion model has been used to evaluate the characteristics of the dispersion and deposition of radioactive materials released into the atmosphere, especially ¹³⁷Cs with its long half-life is considered. It is inferred that the measurements of ¹³⁷Cs in seawater of the Pacific Ocean in 2011 originated from atmospheric deposition, because ¹³⁷Cs directly released into the sea could not have reached the central part of the Pacific Ocean at that time.

Lee, J.-H.; Jeong, K.-S.; Kang, J.; Park, K.-S., and Woo, H.J., 2017. Benzene, toluene, ethylbenzene, xylene, and styrene (5VOCs) distributions at the barrier island system in the Nakdong River estuary, South Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 89–93. Coconut Creek (Florida), ISSN 0749-0208.

Total Volatile Organic Compounds (TVOCs) were extracted from 18 surface sediment samples collected in and around barrier island system in the Nakdong River Estuary (NRE) on the southeastern Korean Peninsula in May 2015. TVOC emissions from sediments were measured using a Thermal Desorption System-Gas Chromatograph-Mass Selective Detector (TDS-GC-MSD) for 30 min at 25°C at the National Center for Inter-university Research Facilities (NCIRF), Seoul National University, South Korea. The thermal extractor (Gerstel, Germany) was equipped with an adjustable oven (temperature, 25–350°C) to heat a glass tube containing the sample. TVOC concentrations ranged from 2.6 to 64.9 ng/g-dry weight (average, 13.2 ± 13.8 ng/g-dry weight), with benzene in the range 0.6 to 0.8 ng/g-dry weight (average, 0.7 ± 0.1 ng/g-dry weight), toluene in the range 0.4 to 1.3 ng/g-dry weight (average, 0.9 ± 0.3 ng/g-dry weight), and xylene in the range 0.0 to 0.8 ng/g-dry weight (average, 0.2 ± 0.2 ng/g-dry weight). No evidence of ethylbenzene or styrene was found at the sampling sites. TVOC concentrations were highest at Sinjado zone, at 64.9 ng/g-dry weight. This area corresponds to back-barrier fringe marsh sediments sorted by location and terrain. Although TVOC levels in many sediments were below the detection limit, this method can be used to estimate their behavior in marine environments. This monitoring in the NRE can draw the necessity of safety management and Sediment Guidance Values (SGVs) establishment as to contributing to remediation of contaminated sediments.

Yang, C.-S. and Ouchi, K., 2017. Application of velocity bunching model to estimate wave height of ocean waves using multiple synthetic aperture radar data. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 94–98. Coconut Creek (Florida), ISSN 0749-0208.

The purpose of this study is to investigate the images of ocean waves produced by synthetic aperture radar (SAR) through the image modulations based on the normalized radar cross section (NRCS) and wave orbital motions, leading to the estimation of ocean wave height. The former is known as the tilt or NRCS modulation and the latter as velocity bunching. In general, the dominant contribution to the image modulation of range travelling waves is the NRCS modulation, and that of azimuth travelling waves is the velocity bunching mechanism. In this study, these two wave imaging mechanisms are investigated using the airborne Pi-SAR (Polarimetric-Interferometric SAR) X-band VV-polarization images of ocean waves around the Miyake Island, Japan. Two images in a same region were produced at approximately 20 minutes interval from two orthogonal directions. One image shows the images of dominant range travelling waves, and the other shows a different wave pattern of azimuth traveling waves. This difference can be caused by the different image modulations of NRCS and velocity bunching. In this study, 18 sub-images are extracted from the two sets of Pi-SAR data, and the directional wave spectra of these sub-images in the orthogonal look directions are compared. We have estimated the dominant wavelength from the images of range waves, and the wave phase velocity from the dispersion relation; the image intensity is also computed by using the velocity bunching model and compared with the data. The comparison of the results strongly suggests that the latter images of azimuth waves are produced by velocity bunching. Furthermore, it is shown that the wave height of 1.4 m estimated from the velocity bunching model is similar to the height of 1.5 m simulated using the MM5 numerical weather model and data assimilation by JWA (Japan Weather Association).

Heo, K.-Y.; Ha, T.; Choi, J.-Y.; Park, K.-S.; Kwon, J.-I., and Jun, K., 2017. Evaluation of wind and wave simulations using different global reanalyses. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 99–103. Coconut Creek (Florida), ISSN 0749-0208.

Sea surface wind plays an important role in oceanic phenomena and coastal environment. There are many sources of meteorological data available, both global and regional, and they differ not only in spatial and temporal resolution, but also in the number of observations included in the reanalysis and in the method of data assimilation used. The performance of the weather research and forecasting (WRF) model and its variational data assimilation system (WRFDA) with two global reanalyses (ERA-Interim and NCEP FNL) used as initial and lateral boundary conditions has been assessed during the period from January to December of 2014. Both WRF model simulations using the ERA-interim and the NCEP FNL are in good agreement with observations, with correlation coefficients for 10-m wind speed ranging from 0.81 to 0.88 and from 0.77 to 0.88, respectively. Both the ERA-Interim and the NCEP FNL are good choices for the model's initial and lateral boundary conditions, while the ERA-Interim simulation showed better results for surface pressure, wind direction and speed. As a result, the ERA-Interim simulation shows better results for the significant wave height and mean wave period. The results of this study should provide some guidance for the improvement and development of WRF simulation, skill assessment of numerical weather prediction systems, and guidance for further research. Furthermore, the reanalyses can be useful for offshore and coastal researchers in estimating extreme sea states and designing specific offshore and coastal structures.

Bao, G.Y.; Huang, H.; Gao, Y.N., and Wang, D.B., 2017. Study on driving mechanisms of land use change in coastal area of Jiangsu, China. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 104–108. Coconut Creek (Florida), ISSN 0749-0208.

Based on the 5 periods of satellite images, land use structure and changes of 3 cities in the Jiangsu coastal area were analyzed, and the relationship between land use structure and environmental factors was analyzed by “CLUE-S model Logistic regression”. The results showed that, for land use change in the past 15 years, the changes in cultivated land, grassland and construction land were the highest. Land use change is mainly located in urban and surrounding areas, followed by farmland mainly located in the coastal zone. This study uses GIS spatial analysis and CLUE-S Logistic regression model analysis, correlation analysis and regression analysis, to identify factors that impact land use in the coastal areas of Jiangsu and the driving mechanisms for this change. A dynamic model of land use, forecast and evaluation was used to understand environmental effects over the next 5–10 years in the Jiangsu coastal area.

Kim, D.H.; Park, K.C.; Kim, I.; Lee, J.L., and Lee, J., 2017. Calculation of rip current warning index by a vector rose diagram. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 109–113. Coconut Creek (Florida), ISSN 0749-0208.

Rip currents, which are sea tides that can carry swimmers into deep water beyond the breaking points, pose an immense security risk to beachgoers around the world. In Korea, rip current forecasting is divided into four warning levels: notice, watch, warning, and danger. However, the numerical results are represented by current vectors, and an additional process is necessary for converting these vectors into a predictive model. The primary goal of this study is to present a method that illustrates how to convert numerically simulated vectors into a rose diagram and how to divide this diagram into four warning levels for rip currents. The proposed method was validated by analyzing the correlation between warning indexes calculated from the present approach and those obtained from the NERiPs. The study was conducted at Haeundae Beach located in Busan, Korea. Different from the NERiPs, which is simply used to forecast the warning levels by the incident-wave conditions, this wave-induced currents model considers morphological effects.

Acharya, T.D.; Yoo, K.W., and Lee, D.H., 2017. GIS-based spatio-temporal analysis of marine accidents database in the coastal zone of Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 114–118. Coconut Creek (Florida), ISSN 0749-0208.

Maritime transportation, including the use of boats, ferries and ships for the transportation, fishing and recreational activities, currently plays an important factor in global economy and is increasing annually. With increase of maritime transportation, the occurrences of marine accident are also increased. Based on worldwide statistical database of marine accidents, Marine Casualties and Incidents (MCI) module published by Global Integrated Shipping Information System (GISIS), the second highest number of accidents have occurred in the coastal zone around East Asian countries, China, Japan and Korea. Especially in Korea, there are many major accidents such as sinking, collision, capsizing, stranding, grounding and explosion etc. which can cause huge damage of human life and property. This study analyses the spatial distribution of marine accidents in more details for coastal zone of Korea in order to illustrate and predict the vulnerable coastal zone for improving costal safety management, planning and decision making. A detailed database with major and minor accidents around coastal zone in Korea collected by the office of Korea Coast Guard (KCG) from 2007 to 2014 were used for the geo-spatial analysis in Geographic Information System (GIS) environment. Two types of spatial analysis, Buffer and Cluster analysis, were performed to visualize the distribution of marine accidents and then to determine the high accident and safety deficient areas. The results from this study can help to determine the common reasons of marine accidents in the coastal zone of Korea, with high vulnerable zone of accident, for risk management, accident prevention and response planning in the future.

Kim, H.; Kim, M.-S.; Kim, Y.-K.; Yoo, S.-H., and Lee, H.-J., 2017. Numerical weather prediction for mitigating the fatal loss by the meteo-tsunami incidence on the west coast of Korean Peninsula. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 119–123. Coconut Creek (Florida), ISSN 0749-0208.

The west coast of Korean Peninsula is an area where casualties and property damages by meteo-tsunamis from the Yellow Sea have been reported. A case in point is the event with an estimated maximum amplitude of 240 cm in Yeonggwang (YG) on 31 March 2007. Many studies have been carried out since then in Korea. These researches focused primarily on the oceanographic aspects (e.g., the resonance between the atmosphere and ocean). They wanted to calculate the resonance effects by the propagation velocity and direction of meteo-tsunami. On the other hand, there were no sufficient atmospheric observation data on the sea, and it was inadequate to explain the various interactions between the atmosphere and ocean. Therefore, the weather research and forecast (WRF) model was used to predict the various detailed meteorological factors (e.g., air pressure, wind vector) on the open sea. This was performed on representative meteo-tsunami events induced by four synoptic weather types. As a result, the numerical weather model, WRF, projected various gridded atmospheric information on the Yellow Sea, and the main atmospheric forcing (e.g., pressure jump line, high pressure system) of the four meteo-tsunami events could be indicated. The numerical weather modeling showed the potential to predict the coastal disaster caused by the meteo-tsunami.

Kim, Y.-K.; Kim, H.; Seo, J.-W.; An, H.-Y., and Choi, Y.-H., 2017. Meteorological analysis of the sea fog in winter season on Gyeonggi Bay, Yellow Sea: A case study for the 106-vehicle pileup on February 11, 2015. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 124–128. Coconut Creek (Florida), ISSN 0749-0208.

The winter sea fog in the Yellow Sea is generally known as steam fog which is created when a cold and dry air mass (e.g., Siberian high) flows over warm sea surface. The status of the atmospheric boundary layer frequently changes by various interactions between atmosphere and ocean, because the west coast of the Korean peninsula has a complicated shoreline by numerous islands and rias coast. Therefore, the sea fog around this area is temporarily generated in unexpected place and it is reduced the visibility severely. The 132 casualties (3 dead, 129 injured) were occurred by the 106-vehicle pileup over the Yeongjong Bridge on February 11, 2015, because of the sea fog on Gyeonggi Bay in the Yellow sea. In this study, synoptic weather analysis and numerical weather modeling were performed to understand causes of sea fog. As a result, the atmospheric boundary layer of Gyeonggi Bay was generally stable because of a stagnant high pressure system when the accidents took place. In addition, low level air under the atmospheric boundary layer was colder than SST on Gyeonggi Bay. It means that the sea fog may be generated by the temperature difference between sea and air.

Park, J.; Park, S.-K.; Choi, J., and Hong S., 2017. New priority ranking algorithm for the deteriorated coastal bridges considering network level. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 129–133. Coconut Creek (Florida), ISSN 0749-0208.

Bridges are currently constructed and designed considering the structural safety required by the design code. However, coastal bridges are continuously deteriorated by many causes such as concrete spalling and exfoliation due to aging, faulty construction, and other deterioration factors. In this study, a prior ranking algorithm is investigated for performing maintenance management of coastal bridges and composed of more reasonable algorithm with studied on previous precedence priority ranking algorithm to realize bridge maintenance. With regard to a rating index of a total of 100 points, appearance defect index and load capacity deficiency was suggested with 40 and 60 point respectively. It is a more reasonable prior ranking algorithm that reflects the load capacity function, traffic of bridges and deteriorated bridge with high degree of deficiency point.

Hong, D.-B. and Yang, C.-S., 2017. Designing an algorithm to generate dynamic intentional grounding zones (DIGOs) for distressed passenger ships in coastal regions. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 134–138. Coconut Creek (Florida), ISSN 0749-0208.

In an emergency case, a passenger ship can be grounded on coastal zone in order to prevent sinking of the vessel and to minimize the injuries and casualties. For the safe and efficient mustering and evacuation of cruise ships, the innovative and reliable systems are needed and discussed in the International Maritime Organization (IMO) for several decadal years. In this paper a novel method is suggested for designating a safe grounding zone, here Dynamic Intentional Grounding Zones (DIGOs), in real-time situation. Thus, DIGO will be a place around passenger ship for effective emergency evacuation in case of uncontrolled marine accident. The research area is the southwest coastal region of Korea including Jindo Island. In this region, there are many passenger ships regularly travelling between islands, large intertidal areas, and eddies caused by rapid changes in currents. DIGOs are automatically calculated in three-dimensional space by combining shipping information (position, draft, etc.) and marine environments (water depth, sea-bottom sediments, and tide level) in real-time. The results of this study can be used to support captains' decision-making during maritime accidents.

Kang, S.K.; Seung, Y.H.; Kim, K.O.; Kim, E.J., and Jung, K.T., 2017. A unified numerical model for typhoon surge in the Northwestern Pacific. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 139–143. Coconut Creek (Florida), ISSN 0749-0208.

A new finite difference modeling system with modified fetched variable grid technique has been developed in order to predict the typhoon induced surge over the Northwestern Pacific. The grid resolution ranges from 18.5 km (10 ′) in open ocean to 109 m (1/17 ′) near the coastal areas of interest, which is quite suitable for resolving the complicated coastal boundaries of the Korean coasts. The total grid number is about 1,350,000 points and the model computation can be effectively carried out with efficient time interval satisfying 1–30 Courant numbers. This system has various advantages over regular finite difference grid system, allowing one to avoid possible numerical errors arising when adopting nested grid technique. Experiments for typical typhoons such as Maemi in 2003 and Nari in 2007 have been carried out to demonstrate that the system works reasonably well. The model results are compared well with observations. It is found that negative surges are generated by typhoons over the shelf, horizontally grow while moving with typhoons, and propagate along the coastline as Kelvin waves on arriving at the coast. The alternating positive and negative surges, occurring in the southern Korean coasts including Pusan area and also along the Japanese coasts of the Korea Strait, seem to be due to the geometric effect by the East/Japan Sea.

Kim, K.O.; Yuk, J.-H.; Jung, K.T., and Choi, B.H., 2017. Swell propagation caused by typhoon passage to the Yellow and East China Seas. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 144–148. Coconut Creek (Florida), ISSN 0749-0208.

Typhoons generate big swells frequently propagating over the East China Sea, the wide continental shelf sea with depth shallower than 200 m. The characteristic features of swell propagation into the Yellow and East China Seas caused by typhoon Herb in 1996 has been investigated applying a ray-tracing technique and a spectral wave model (SWAN) with an unstructured-mesh grid system. This study discusses the generation and propagation of the swells into the Yellow and East China Seas using the integration of ray trajectories and model-based simulated wave. Calculated and observed wave heights and periods at Gadeokdo, Korea are found to be in reasonable agreement with each other.

Kim, M.-S.; Kim, H.; Kim, Y.-K.; Yoo, S.-H.; Eom, H.-M., and Woo, S.-B., 2017. Determination of accurate arrival time of meteotsunami event in Yellow Sea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 149–153. Coconut Creek (Florida), ISSN 0749-0208.

According to a recent study by the Korean Meteorological Administration (KMA), unforeseen losses to property and human lives along the west coast of Korea in March 2007 were caused by meteotsunamis that originated at Shandong, which is located in eastern China. The determination of the arrival time of meteotsunamis in Yellow Sea is very important to protect human life and limit economic losses in coastal areas, because the analysis of meteotsunami propagation is primarily dependent on the method of arrival time. In this study, the meteotsunami event of March 29–31, 2007, the most powerful meteotsunami event reported in the Yellow Sea, was selected to find the optimal method of calculating the meteotsunami arrival time. It is difficult to estimate the arrival time of a meteotsunami that is commonly observed as a non-stationary signal in a time series without any specific criterion. To find a quantitative and reasonable method of estimating the arrival time, the propagation direction of the meteotsunami was analyzed using the arrival time at each tidal station derived from the absolute and relative threshold of the sea level oscillations in the meteotsunami frequency bands. The results indicated that the meteotsunami propagation derived using the relative threshold which defines the arrival time as the time when the amplitude of the sea level oscillation exceeds 3 standard deviations was more similar to the propagation pattern of the high rain rate field than other thresholds.

Lee, J.; Park, S.-K., and Hong, S., 2017. Numerical simulations of local scour at Samsan Bridge piers in Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 154–158. Coconut Creek (Florida), ISSN 0749-0208.

The Samsan Bridge connects Ganghwa Island and Incheon in the mid-western region of South Korea. The country is making an effort to improve access to the island from its major cities, and the construction of the bridge is part of that process. External factors such as wind waves, tide currents, currents, and scour depths around piers should be considered in the construction of a bridge. In order to obtain scour depth values around bridge piers, this study conducted numerical simulations on morphological changes using the SADEM (SAnd Deposit and Erosion Model). The morphological changes were calculated by solving the conservation of sediment transport equation. A field measurement was performed at the Seokmo channel in the Han River estuary (South Korea) to verify the numerical results. A 153×210 grid system with a coarse grid size of 22.8 × 30 km was used in the SADEM. The maximum stream velocities of 10, 50, and 100-year flood return periods during the ebb tide contributes to sediment mobilization in the Seokmo channel. The maximum scour depth was calculated to be 9 m around the central bridge's pier during the flood ebb for the 100-year return period. This was due to the upstream discharge during river flooding. The results of the numerical simulations are expected to be objective indicators of optimal design, construction, and future maintenance of the Samsan Bridge.

Song, M.-S.; Yun, H.-S.; Kim, T.-W., and Cho, J.-M., 2017. Algae inflow monitoring using satellite images for the process control of the Gijang desalination plant in Busan, South Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 159–163. Coconut Creek (Florida), ISSN 0749-0208.

Climate change has recently been taking place due to the sudden rise of water temperature resulting from global warming and the red tides adversely affected the seawater desalination plant directly or indirectly every year. Harmful Algal Blooms (HABs) occur if the perishable organic pollutants, minerals, and growth stimulating substances are abundantly dissolved in the water and if solar radiation, water temperature, salinity, and other environmental conditions are met. Once the algae are agglomerated by the wind and tide, high-density red tide occurs. This may also cause damages to the desalination plants. RO membrane in the main process cannot be cleaned by the chlorination for membrane cleaning because the material of RO membrane is polyamide. Therefore, the algae and microorganisms contained in seawater have a negative impact on membrane fouling. Accordingly, pre-treatment method for blocking the inflow of algae by monitoring the occurrence of HABs is more effective than post-processing method that is used for cleaning after the membrane is already contaminated. In this study, algae inflow monitoring was carried out through satellite image analysis looking for an appropriate analysis algorithm of chlorophyll-a concentration by using the Geostationary Ocean Color Imager (GOCI) Data Processing System (GDPS) for the process control of Gijang desalination plant. Accordingly, the chlorophyll-a concentration analyzed by OC2 algorithm for algae inflow monitoring is the most suitable algorithm.

Ha, T.; Heo, K.-Y.; Jeon, J.S., and Kang, S., 2017. Numerical modelling of large swell waves using different atmospheric reanalysis data in East Sea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 164–168. Coconut Creek (Florida), ISSN 0749-0208.

Recently, large swell waves have been attracted by many engineers and scientists in South Korea since the eastern coast of the Korean Peninsula has been frequently damaged by large swell waves for several years during winter season. These waves were occasionally higher than 3 m and could be very dangerous for people in beach areas. It has been identified that these waves originated from a certain cyclone passing over East Sea in recent researches. However, an apparent developing mechanism of large swell waves in East Sea is still remained unidentified. Numerical modelling of water waves using the third generation wave model is a convenient source for analysis of wave behaviors in the ocean. In this study, two well-known global atmospheric reanalysis data (ERA-Interim and NCEP FNL) were employed to simulate large swell waves in East Sea. Since sea surface wind is generally regarded as the most important source to wave models, different global reanalysis data should be carefully applied to wave models for better performance. Numerical results of wave models using two different reanalysis data were compared with available observational data and their performance reproducing large swell waves was evaluated both qualitatively and quantitatively. Both simulated wave products using ERA-Interim and NCEP FNL data were reasonably agreeable with corresponding observational data while wave products employing ERA-Interim data qualitatively represented development of observed wave profiles slightly better at certain locations than those employing NCEP FNL data. On the other hand, wave products using NCEP FNL data quantitatively represented observational wave heights slightly better than those using ERA-Interim data during the extreme events.

Jho, M.H.; Kim, G.H.; Yoon, S.B., and Hyun, S.G., 2017. Selection of ship evacuation area to construct tsunami emergency action plan. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 169–173. Coconut Creek (Florida), ISSN 0749-0208.

When a tsunami occurs and starts to propagate towards coastal region, a tsunami warning is issued. Then, the captain of ship in a port is advised to make a decision in accordance with the situation. If a captain does not take his ship out of port, more damage to the infrastructures of a port, other ship and even itself is likely. To reduce additional damages, tsunami action plan is essential to lead ships out of a port. However, exact procedures to evacuate are not provided in the evacuation action plan. In this study, how to select a ship evacuation area outside of a port will be discussed based on wave height, tsunami-induced currents and the behavior of ships. To illuminate the selection criteria to locate a safe zone, numerical simulation of the 2011 East Japan Tsunami is performed using a dispersion-corrected finite difference scheme with the time-dependent fault parameters. Moreover, Masan and Jinhae bays are selected as sample cases in order to establish the base of ship evacuation action plan in Korea.

Yoon, J.-S.; Kim, T.-W.; Cho, W.C., and Lee, W.D., 2017. Effect of power cooling water to the ecosystem of Youngil Bay and Hyeongsan River estuary in South Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 174–178. Coconut Creek (Florida), ISSN 0749-0208.

The POSCO (Pohang Steel Company) discharges about 1,000,000 m³/day of 30 °C power cooling water to the estuary of Hyeongsan River, which is located in the southeastern region of South Korea. The thermal effluent is mixed with sea water and diffused to Youngil Bay. At the beginning of the 1990s, the thermal effluent affects brackish water zone of Hyeongsan River and Youngil Bay and becomes a main cause of red tide in this sea area, which starts to occur from January. Besides, the thermal effluent also affects coastal sea water quality and ecosystem raising the surrounding sea water temperature. In this study, we figured out the present circumstances and problems in the brackish water zone of Hyeongsan River estuary and Youngil Bay, which resulted from the thermal effluent in winter season. We also found out the cause of red tide on the basis of 8 measured categories on site, such as temperature, salinity, DO, COD, TN, TP, chlorophyll-a, and flow velocity, and performed a numerical analysis using the measured data to precisely investigate the occurrence mechanism of red tide. The results show that intrusion range of saline wedge in the lower layer of water depth is reduced in summer season because of increased river discharge, however, the river water and thermal effluent is diffused to Youngil Bay forming a typical estuary front with stratified condition. On the contrary, in winter season, a constant vertical density distribution, resulting from a strong mixing of the upper and lower water layers, is formed at downstream of the thermal effluent outlet. However, a thermohaline front, developing a less denser distribution than that developed in the strong mixing area, is formed at downstream of the strong mixing area. The formation of thermohaline front induces flow stagnation in Youngil Bay and subsequently obstructs river discharge to Youngil Bay. Thus, a mass of chlorophyll-a is bred by the thermal effluent and consequently a red tide.

Hur, D.S.; Cho, W.C.; Yoon, J.S.; Kang, C., and Lee, W.D., 2017. Applicability of multiple submerged narrow-crested breakwaters for reduction of mean water level in rear side and flow control. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 179–183. Coconut Creek (Florida), ISSN 0749-0208.

In this study, to confirm the applicability of multiple submerged narrow-crested breakwaters (SNCBs), a 3-D numerical simulation was conducted. The numerical simulation used the numerical model developed for analyzing the 3-D flow structure around the submerged breakwaters. In addition, to verify the validity and effectiveness of the numerical model, the wave height distribution and mean water level distribution around impermeable submerged breakwater (ISB) and permeable submerged breakwater (PSB) were compared with the results of the numerical model experiment. As a result, the simulated results accurately realized the experimental values. The numerical simulation was conducted by applying the multiple SNCBs and common PSB for comparative analysis of the effectiveness on flow control and increased mean water level in the rear side, respectively. When the SNCBs are installed by more than two rows, the flow control was better than that achieved by installing PBS. However, the wave reflection was high, and the water level difference between onshore and offshore increased, owing to increased water level in the rear side. Based on this, an opening was installed on the multiple SNCBs, for the reduction of water level in the rear side. As a result, an outgoing flow toward the open sea was generated, which reduced the mean water level in the rear side. When W/L_r ≥ 0.2, the mean water level difference between onshore and offshore decreased, compared to the case of the PSB. Therefore, when appropriately installing the multiple SNCBs, whose applicability has been confirmed in this study, this can become one of the methods that can replace existing PBSs, which are bulky in size and expensive to construct.

Shim, J.-S., Min, I.-K., and Yoon, J.-J., 2017. Hydraulic experiments on sinkable floating storm surge barrier under various wave actions. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 184–188. Coconut Creek (Florida), ISSN 0749-0208.

A sinkable floating storm surge barrier is a new type of structure designed to reduce coastal disasters from storm surges. This barrier usually lies on the seabed, but its buoyancy allows it to rise up as a seawall when a storm surge occurs. A sinkable floating-type storm surge barrier consists of a buoyant main body connected to a foundation structure on the seabed by a hinge. In this study, the wave forces acting on the barrier were experimentally investigated. To evaluate the wave reflection and transmission from this buoyant floating-type storm surge barrier, hydraulic experiments were performed under regular and irregular wave conditions. The wave blocking capabilities of the sinkable floating barrier against surges were confirmed, and the characteristics of the barrier motion and wave pressure were clarified by changing the wave condition. Based on the hydraulic experiments, it was found that this type of barrier was effective at wave transmission, as well as reflection. It was shown that a sinkable floating barrier placed at the mouth of a bay as a storm surge barrier can be expected in the future. However, further detailed hydraulic and numerical experiments are also needed to accurately predict the barrier motion under combined wave–current conditions.

Lim, C.; Park, S.-H.; Kim, D.-Y.; Woo, S.-B., and Jeong, K.-Y., 2017. Influence of steric effect on the rapid sea level rise at Jeju Island, Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 189–193. Coconut Creek (Florida), ISSN 0749-0208.

According to a report by the Korea Hydrographic and Oceanographic Agency (KHOA), the sea level rise in west coast (1.31 mm/yr), east coast (2.69 mm/yr) and south coast (2.05 mm/yr) of Korea are different. Especially, the seas around Jeju Island show one of the most rapid increase of sea level rise in recent years. This investigation on the data from Jeju and Seogwipo tidal station indicated that the sea level rises around Jeju and near Seogwipo were 5.63 mm/yr and 3.75 mm/yr, respectively. This shows that the northern and southern parts of the island have different temporal rates of sea level rise. The purpose of this research is to analyze the influence of the steric effect caused by density change in the water to the rate of sea level rise, by using sea temperature and salinity data measured by the National Institute of Fisheries Science (NIFS). It is found that the trend of seawater density variation near Jeju Island changed by the time of around 2006 and so does the sea level rise, indicating that there is a meaningful correlation between sea level rise and density variation. The rate of steric height rise by the density were calculated, resulting in a 15.8% and 23.2% of sea level rise in Jeju and Seogwipo, respectively.

Park, J.R.; Jeon, H.S.; Jeong, Y.M., and Hur, D.S., 2017. Numerical analysis on energy dissipation of tsunami through vegetation zone. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 194–198. Coconut Creek (Florida), ISSN 0749-0208.

We have improved a 2-D Numerical Wave Tank (NWT) based on a Porous Body Model (PBM) for the simulation of energy dissipation during the interaction with a tsunami. In order to quantitatively evaluate the energy dissipation by vegetation drag during the process, the fluid resistance with regard to the vegetation and the vegetation drag coefficient according to the Reynolds number were applied. Moreover, to confirm the validity and effectiveness of the improved NWT, the results were compared with the existing numerical experimental results of tsunami vegetation interaction. The comparison showed that the water waveforms of the tsunami around the vegetation zone well are well simulated. As a result, the height of tsunami, the width, the density of vegetation, the reflection of the tsunami by freeboard, and the reflection and transmission characteristics of the tsunami were confirmed. In addition, the characteristics of the decrease in the energy of the tsunami as it passes through the vegetation zone were analyzed. As the vegetation width, height, and density increase, the transmission coefficient decreases, the decrease in the energy increases, and the reflection coefficient does not change significantly. In addition, since a vegetation zone with a large porosity gradually decreases the energy, the decrease in the energy becomes clear as the vegetation width increases.

Lee, J.K.; Lee, I., and Kim, J.O., 2017. Analysis on tidal channels based on UAV photogrammetry: Focused on the west coast, South Korea case analysis. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 199–203. Coconut Creek (Florida), ISSN 0749-0208.

In the coastal waters of the Republic of Korea, the incidence of marine vessel accidents has been increasing in recent years, due to increased maritime traffic and complex terrain conditions. With the proliferation of marine leisure activities and the maritime conditions such as tides, rocks, typhoons, tsunamis, there are various types of marine accidents that have not been experienced before. Therefore, it is imperative to establish an information based system (like digital map or 3D distribution map) that can be utilized in marine safety fields such as accident and disaster prevention. In this investigation, it will be discussed the safety mapping for tidal channel connected directly with human life. A tidal channel is a waterway where occurs by the process of ebb tide and flood tide in the tidal flats. Since the shape (included exact depth) of tidal channel cannot be identified when a tide comes in, it must be considered as the main causes of the summer drowning fatalities. A map for tidal channel has been proposed by a 3D distribution map that can be identified the shape and location of tidal channel, and also, this map should be offered to marine tourist and maritime safety authority. A cartography based on image collected by manned aerial Photogrammetry or satellite has the insoluble limitations in terms of economy, time constraint and periodic for measurement. Due to temporary erratic overflow through the tidal amplitude, the information for tidal channel cannot be monitored in real time. Therefore, in the present investigation, a UAV (Unmanned Aerial Vehicle) recently been actively used in the field of spatial information is considered in analyzing the status of tidal channel. First of all, the DEM (Digital Elevation Model) of tidal flats generates through UAV based auto-image, the distribution map for tidal channel expresses different colors by the height of topographic. A tidal channel encoding specific color (normally red) can be provided dangerous signal to the user. It can be identified the sea leveling at the certain time that can be measured whole shape of tidal channels, and also, provided a more realistic and readable information on tidal flats. The information provided through the tidal channel map was verified by comparison with the VRS GPS positioning solution. Since information such as the exact distribution location and shape should be considered as the first priority, the coordinates of the tidal channel was compared with the previously proven method, VRS GPS. As a result, it is determined that the location of attribute information and the 3D shape analysis value analyzed by UAV image can fully provide information within the convergence range. In this investigation, UAV image can be estimated on the location and shape of tidal channel by observing exactly at the time zone for flood tide. It can be fully expected that the UAV is contributed to preventing the marine accident in advance by maximizing the latent properties with regards to periodicity, accuracy, operation convenience and economy.

Ahn, Y.; Shin, B., and Kim, K.-H., 2017. Shoreline change monitoring using high resolution digital photogrammetric technique. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 204–208. Coconut Creek (Florida), ISSN 0749-0208.

Shoreline change has been measured with conventional surveying techniques such as Total station, GNSS, EDM etc. These measurements provide short/long term variation of nearshore evolution which enables us to estimate erosional and accretion sediment volume of the beach. This observation of ocean morphology currently has been utilized through the advance of optical imaging system and related digital image analysis. When deployed with proper viewing geometry, ground based digital imaging system can provide higher spatial/temporal resolution of shoreline change than satellite remote sensing data. In this study, we focus on generating time series of shore line change in Songjung beach in Busan, Korea where two DSLR imaging station have been successfully installed nearly at the end of each beach span. Via single photo photogrammetric techniques such as lens calibration, interior/exterior orientation, feature tracking, projection toward water surface, we aim to (1) calibrate out time lapse camera system, (2) verify with conventionally observed shorelines and finally (3) quantify the trend of ocean morphology in target sites. Understanding that shoreline monitoring system compliments existing conventional survey, its pros and cons should be treated as integrated method with conventional method.

Lee, G.; Choi, J., and Jun, K.S., 2017. MCDM approach for identifying urban flood vulnerability under social environment and climate change. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 209–213. Coconut Creek (Florida), ISSN 0749-0208.

This study examines a method for conducting flood vulnerability assessments based on urban environmental and social characteristics. In other words, the purpose of this study is to analyze the characterization of flood damage to a city and determine assessment factors, thereby establishing a vulnerability assessment procedure. In order to consider urban environments in the future, the trend for socio-economic changes and changes in rainfall patterns due to climate change are included. The established assessment procedure consists of the following three steps: criteria and weights determination using Delphi and Entropy methods, data acquisition and construction of database, and vulnerability quantification and priority decision making. Future precipitation is estimated from the RCP scenario, and the indexes that indicate social and economic changes in a region, such as population change and urbanization, are calculated using a scenario based on the data from Statistics Korea. In this study, the assessment method was applied to the Dorimcheon basin in Seoul, Korea, where inland flooding caused substantial damage in 2011. It was found that the influence of increased precipitation (due to climate change) on flooding risk was less than that of the increase in vulnerability factors caused by social and economic development. The approach used in this study can suggest preferred regions or objects for urban flood management by considering characteristics of each region and recognizing intrinsic vulnerability factors in advance.

Hung, N.T.; Vinh, B.T.; Nam, S.Y., and Lee, J.L., 2017. Cause analysis of erosion-induced resort washout on Cua Dai Beach, Vietnam. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 214–218. Coconut Creek (Florida), ISSN 0749-0208.

On an eroding beach, high waves can completely wash out beaches, swimming pools, and resorts. Cua Dai shore, which is located immediately north of Thu Bon river mouth in central Vietnam, has eroded on the order of hundreds of meters in beach width. The present study estimated the erosion rate of sediment volume into the estuary through the Thu Bon river mouth by using recent satellite images, and utilized a shoreline change model to reproduce the erosion of shoreline near the river mouth. Results are in good agreement with observed data. The numerical model is modified by including the equilibrium angles that were obtained from a static shoreline equation of parabolic shape. Through the sediment conservation rule, the main cause of shore retreat is found to be sediment loss in the Thu Bon river estuary with the reduction in river sediment. The possible causes for this type of sediment loss are mining in the estuary and reduction of river flow action against waves in the river mouth with the reduced sediment supply. Proper management of Cua Dai beach requires the development of a monitoring system to fully understand beach dynamics and to mitigate the further resort washout owing to background erosion.

Lee, W.D.; Cox, D.T., and Hur, D.S., 2017. Numerical model study on the wave and current control by coastal vegetation. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 219–223. Coconut Creek (Florida), ISSN 0749-0208.

In this study, three-dimensional numerical simulations were conducted to investigate the effect of the coastal vegetation on the wave and current controls. The model was modified to apply three-dimensional Navier-Stokes solver based on porous body model for the direct simulation of the wave energy dissipation through the vegetation. The new formula of a vegetation drag coefficient based on the wave-vegetation interaction was proposed through the hydraulic model tests and the formula was implemented to the model. The modified numerical model was tested and the results were compared with the experimental results to verify the numerical model capability. The model results well reproduced the wave energy dissipation inside the vegetation zone. Moreover, the numerical modeling was also conducted for the hydrodynamics on permeable submerged breakwater and the model results were compared with the results of vegetation. Inside the vegetation zone, the wave energy slowly decreased and the water level behind the vegetation was not increased seriously. Since the vegetation reduces the wave energy gradually, the width of the vegetation zone is an important factor for the effective control of the wave energy. Because the water level behind the vegetation zone did not increase too much, the return flow was small compared with that in the gap between the submerged breakwater cases. Therefore, if we deploy coastal vegetation effectively, this may be a better measure than coastal structures in terms of effectiveness and economy.

Wu, G.; Liang, B.; Li H.; Lee, D.-Y., and Guo, W., 2017. Determining how offshore shoals control rip current generation in an embayed beach. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 224–228. Coconut Creek (Florida), ISSN 0749-0208.

In this study, the generation of rip currents at Haeundae Beach, Korea, is investigated using an advanced, non-hydrostatic wave-resolving model SWASH. It is found that the presence of offshore shoals leads to strong wave refraction, creating significant alongshore wave height variations and mega-scale rip current systems. The modeled rip currents occurring locations correspond well with the low wave height areas. The rip currents persist even if the surf zone rip-channel topography is smoothed, with very similar spatial patterns and occurring locations compared with those generated under the original bathymetry. We argue that the mega-scale rip currents generated at Haeundae Beach are controlled by the offshore shoals, while the effect of the rip-channel morphology is minor. An idealized embayed beach with an offshore Gaussian-shape shoal is further designed to study the shoal characteristics on the resulting rip current patterns. Primary numerical results show that wave focusing and spreading happens in the presence of the shoal, leading to the formation of rip currents in the wave shadow area behind the shoal. However, a shallow shoal closer to the shoreline favors wave breaking on top of it and strong onshore-directed wave-induced currents, instead of offshore-directed rip currents.

Shin, S.; Nam, J.; Son, S.; Kim, I.H., and Jung, T.-H., 2017. Field observation and numerical modelling of rip currents within a pocket beach. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 229–233. Coconut Creek (Florida), ISSN 0749-0208.

Understanding the occurrence mechanism of rip currents are very important in terms of the sediment transport and the water safety issues. In order to investigate the rip current occurrence mechanism, field observations were carried out at Chunjin beach and a numerical model was employed to simulate rip currents by using the field observation data. The collected data set includes the beach topography, bottom bathymetries, shoreline, sand sample, and incident waves for each season. The field observation data showed the spatiotemporal variations of shoreline and sand bars. The results also showed that the rip currents were generated near the crescentic sand bar. For better understanding the mechanism of rip currents, numerical simulation using phase- resolving, three-dimensional 3D Non-Hydrostatic WAVE Model (NHWAVE) was also carried out. The model considered incoming wave conditions collected from the field observation to look at the nearshore current generation patterns. Through this numerical model, this study could have investigated vertical profiles of nearshore wave-induced current while the field observation data represent depth uniform currents. The numerical simulation showed a good agreement with the field observation and provided useful information for nearshore circulation.

Ryu, Y.; Jung, T.-H., and Kim, Y.-T., 2017. Kinematics of overtopping flow on breakwater top. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 234–238. Coconut Creek (Florida), ISSN 0749-0208.

This study carried out experiments to investigate the behavior of overtopping flows in the vicinity of a caisson breakwater with dissipating blocks. Overtopping flows over a breakwater show horizontal momentum that causes significant damage to objects such as buildings, vehicles, or persons on the top. There is a need to understand overtopping flows on the top related to wave conditions to mitigate damage. This study measured front velocity and impinging distance of overtopping flows by monochromatic waves to examine flow behavior on the top and estimate overtopping flows over the rear slope of the breakwater model in varying wave conditions. Relationships among the parameters were also used to induce empirical equations through dimensionless analysis.

Kim, D.-Y.; Park, S.-H.; Woo, S.-B.; Jeong, K.-Y., and Lee, E.-I., 2017. Sea level rise and storm surge around the southeastern coast of Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 239–243. Coconut Creek (Florida), ISSN 0749-0208.

The sea level rise around the Korean peninsula has become a significant factor that can have a catastrophic impact on low-lying coastal regions. The risk of storm surges can be intensified by rising sea levels, which will create more damaging flood conditions in coastal areas. This study focused on the long-term variations of the mean sea level (MSL) and the annual maximum surge heights (AMSH), which were influenced by global warming and strengthening typhoons. The trends of MSL and AMSH were estimated using the sea level data at eight stations along the southern and eastern coast of Korea over the past 40 years (~2014). The trend was on average 2.31 mm (exclude Pohang) and 2.59 mm per year, which were significant within the 95% confidence level based on linear regression. The areal average rise of the MSL was 2.32 mm and 2.31 mm (exclude Pohang) per year in the south and east coast of Korea. The average rise of AMSH in the southern coast ( 3.71 mm/year) was higher than the eastern coast ( 1.48 mm/year) because the southern coast lies in the direct path of typhoons. Statistical analysis showed that 41% ~ 58% of the AMSH occurred during the typhoon event. The AMSH were relatively low during the last decade due to the typhoon landfall frequency and reducing intensity. Overall, the surge heights (extreme sea levels) at southeastern coast of Korea are likely to be affected by geographical or regional atmospheric adjustments in accordance with global climate change.

Xu, Z.; Wang, J.; Liang, B., and Chen, Y., 2017. Effects of offshore sand motion on wave runup from reflective beaches by using XBeach model. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No.79, pp. 244–248. Coconut Creek (Florida), ISSN 0749-0208.

The safety of the beachgoers is affected by the high speed swash motion and wave run-up at the beach. As many field studies show, complex of nearshore beach profile and sand offshore motion, such as sandbars and its motion, may influence swash processes by changing break point. But few detailed research was made on the reflective beaches (0.3 < ξ₀ < 4.0). In the present work, a series numerical tests were carried to investigate the effects of sand offshore motion by XBeach model. The runup results of XBeach model at different time with sand offshore migration were analyzed, and the 2% runup (R_2%) predicted by XBeach model and empirical formula are compared. The effects of sand offshore migration on runup components (wave setup ⟨η⟩ and swash S), and wave energy spectrum were discussed. The milder beach gradient β which induced by the sand offshore motion is not only the reason to make the runup height decrease, but also some other effects induced by sand offshore motion. The magnitude of wave spectrum decreases with sand offshore migration, and the trend wave energy shifts to the infra-gravity band becomes more evident.

Lee, J.L.; Kim, I.H.; Yeon, Y.J., and Lee, J., 2017. Monitoring and analysis of bacterial communities during a summer season on Gyeongpo Beach. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 249–253. Coconut Creek (Florida), ISSN 0749-0208.

A number of tourists visit beaches in the summer to enjoy sea bathing. However, numerous accidents occur on the eastern coast because of the topographical characteristics of the beach, and most accidents are caused by rip currents. Additionally, in the summer, as many tourists prefer beaches near swash zones, exposure to non-point pollutant sources can occur, significantly harming the health of visitors. Enterococci have shown the strongest correlation to gastrointestinal symptoms in a study examining the relationship between swimming-associated gastrointestinal illness and microorganisms. The U.S. Environmental Protection Agency found a direct relationship between the density of E. coli and enterococci in surface waters and increased swimmer-associated gastroenteritis. These reports suggest that E. coli and enterococci can be used as bacterial indicators compared to total coliform. Therefore, in this study, the safety of beach seawater was evaluated using E. coli and enterococci as bacterial indicators. Enterococcus and E. coli were isolated during the summer holiday season from the Gyeongpo Beach located on the eastern coast of Korea. The results indicated that the source of pollution near a swash zone, where people are crowded, was larger than that at the dry beach and near swimming zone.

Kim, T.-W.; Kim, J.-H.; Song, M.-S., and Yun, H.-S., 2017. Convergence technique study on red tide prediction in the littoral sea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 254–258. Coconut Creek (Florida), ISSN 0749-0208.

Active research has been conducted on tracking red tides by combining remotely sensed satellite images and numerically predicted ocean currents. Recent ocean observing satellite images have low spatial resolution and temporal limitations. Such convergence technologies are developed to overcome these shortcomings. Chollian, which is the world's first oceanographic satellite capable of observing ocean surface in a “geostationary orbit”, can detect the current expansion and intensity of Harmful Algal Blooms (HABs). This Geostationary Ocean Color Imager (GOCI) can combine HABs patch with tidal current to predict where the bloom will travel on the Korean peninsula coast because it takes photographs at 500 m spatial resolution 8 times a day. HABs initially occurred at 9 a.m. on August 17, 2015, and were most likely to flow into the seawater desalination plant at 1 p.m.. Intake managers who operate and maintain (O&M) seawater desalination plants can track the inflow possibility hourly using this convergence technology. The inflow possibility was predicted by Linear Directional Mean (LDM) spatial analysis in GIS environment. This product can provide seawater intake managers with timely information as a useful decision-making tool.

Yoon, J.-J., 2017. Numerical study of rip current generation at Daecheon Beach, west coast of Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 259–263. Coconut Creek (Florida), ISSN 0749-0208.

Daecheon Beach in Boryeong, Korea, is one of the most popular places on the west coast of Korea. The world famous “Mud Festival” attracts visitors in summer and this beach has many tourists throughout the year. However, the irregular occurrence of rip currents threatens swimmers during every summer season. Two people were swept away by fast moving rip currents in August 2010, and could not be rescued. To investigate the dominant mechanism of rip currents in this region, a numerical simulation was carried out using the non-hydrostatic model Surface WAves till SHore (SWASH), with observed wave and topographical data. In this paper, the applicability of SWASH for modeling wave transformation and rip current circulation near the shallow foreshore is investigated. Assuming that rip current dynamics are controlled by a combination of variations in wave dissipation, tidal currents, and morphological flow constriction, this study tested the effects of wave parameters (such as height, period, and direction) on rip current generation. Rip currents were simulated when longshore currents flowed out through a channel with very small wave energy in the seaward direction. The occurrence of rip currents increased under conditions of higher waves and longer wave periods. In the case of wave direction, cases were tested from northwest to southwest, and the spatial characteristics of the simulation results are presented. Rip currents have often appeared in SW types of wave direction conditions. The change of the wave direction changed the locations of rip current generation. However, the influence of topographic features has not been shown significantly at Daecheon Beach because the bathymetry of the area is shallow and the bottom slope is mild.

Wang, Z.; Yin, Z.; Chen, Y., and Yang, B., 2017. Numerical study on the effects of submerged breakwater on wave overtopping. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 264–248. Coconut Creek (Florida), ISSN 0749-0208.

In order to protect beach or mud coastlines, submerged breakwaters are built in the world widely. When the submerged breakwater is designed, one important issue having to be analyzed is wave overtopping of coastlines or coastal preventing structures since the wave overtopping is very dangerous for people or structures on the potential coastal zones with probability of wave overtopping appearing. A 2-D numerical wave flume has been established based on Flow-3D software to investigate effects of incident wave parameters in front of the submerged breakwaters, slope of the beach and the submerged breakwaters themselves, respectively. The numerical wave flume has been verified by the theoretical data of wave equation and wave frequency spectrum of physical experiment. The computational results fitted well with the theoretical data. The calculated values of the overtopping are in good agreement with the physical model test values under the conditions of random wave. The verified model has been used to calculate the wave overtopping under the different wave height, wave period and slope of the beach. The results of numerical model test indicate that the wave overtopping without a submerged breakwater is much more than that with one for random wave approaching, which is similar as phenomena found in physical experiments. The relationship between wave overtopping and wave height, wave period, slope of the beach was discussed. And a new empirical formula to calculate the overtopping was fitted based on the method of dimensional analysis.

Kim, H.; Lee, S.B., and Min, K.S., 2017. Shoreline change analysis using airborne LiDAR bathymetry for coastal monitoring. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 269–273. Coconut Creek (Florida), ISSN 0749-0208.

Shoreline is commonly defined as the boundary between land and sea. As a consequence of global climate changes and human interventions, shoreline is constantly changing by erosion and accretion. Korea is also faced with the coastal erosion problem. Therefore, the coastal monitoring method needs to quantitatively analyze the shoreline locations and differences in past and present. For this, our research for coastal monitoring is to adopt the quantitative analysis of shoreline change using airborne bathymetry LiDAR. Bathymetry data is useful for coastal monitoring, since the water depth provide geospatial information of 3D point cloud data, including the shallow water as well as the near-shore. In this study case, bathymetry data was collected by CZMIL in 2013 at Gyeongpo and Wonpyeong beach. Topography data collected by ALTM in 2010 was used to check trend of shoreline change at the same sites. In order to extract shoreline position from the LiDAR data, the shoreline definition is referenced as AHHW (Approximate Highest High Water). As a result, East coast has eroded about 347 m² of Gyeongpo beach and about 23819.5 m² of Wonpyeong beach. From this analysis, the average annual rate of erosion is 1.6 m per year. Shoreline change at East coast resulted in a landward retreat by 5 m at the last four years.

Song, J.I.; Kim, J.W.; Yoon, B.I., and Woo, S.-B., 2017. Temporal variability of velocity structure according to artificial discharge in Yeoungsan Lake. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 274–278. Coconut Creek (Florida), ISSN 0749-0208.

An estuary dyke makes a closed environment in an artificial lake such as Yeoungsan Lake, thereby restricting material circulation. Because the artificial discharge serves as an external force with dominant effects on the internal material circulation of the lake, the effects of this discharge need to be investigated. This study analyzed the water temperature and velocity data for Yeoungsan Lake to identify the change in water temperature due to the discharge and the mechanism of the two-layer velocity structure found after the discharge. During the discharge, the downstream velocity and water temperature of the bottom layer of Yeoungsan Lake rapidly increased. After the discharge, a two-layer velocity structure repeatedly appeared, with flows in the downstream direction at the surface layer and upstream direction at the bottom layer. The water temperature, which rapidly increased at the bottom layer during the discharge, rapidly decreased after the water was completely discharged. Consequently, the water temperature after the discharge remained higher than that before the discharge. The inflow of water mass from the upstream area during the discharge led to a spatial density difference and generated the two-layer velocity structure after the discharge. The vertical mixing due to this two-layer velocity structure after the discharge increased the water temperature at the bottom layer and decreased stratification.

Tong, C.; Meng, Y.; Chen, G., and Yan, S., 2017. Spectral analysis of wave uplift load on exposed jetties in waves and currents. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 279–283. Coconut Creek (Florida), ISSN 0749-0208.

This paper presents the results of an experimental investigation on the effect of the interaction of currents with oblique waves on wave uplift load spectrum. A series of laboratory tests were carried out in a wave tank for jetty model in various conditions of wave and current. It is shown that the peak spectral density of wave uplift load is modified due to the influence of angle of wave attack. The variation of measured wave uplift load spectrum with the current direction indicates strong current influence on waves. The results reveal that current and oblique wave change the zeroth spectral moment of wave uplift load. The asymmetry in the values of the relative zeroth moment of wave uplift load m₀(F)/(ρgH_sA)² with respect to the angle of wave attack 90-α is observed in current field. Higher m₀(F)/(ρgH_sA)² was measured when generating waves against current while lower m₀(F)/(ρgHsA)² was measured when generating waves along current. Higher deck has a smaller m0(F)/(ρgHsA)² with lesser energy compared to lower deck.

Suh, S.-W.; Kim M.-J., and Kim, H.-J., 2017. Prediction of sand beach variations by coupling of hydrodynamic and morphological models during extreme storms. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 284–288. Coconut Creek (Florida), ISSN 0749-0208.

Beaches are constantly affected by hydrodynamic forcing. Among various factors, a wave impact is the major reason for beach formation and erosion. In order to provide efficient coupling for the morphological variations in beaches, we consider an unstructured ADCIRC SWAN model and an orthogonal curvilinear XBeach model. When coupling these heterogeneous models, external Perl scripts are implemented to automatically convey simulated extreme wave and tide conditions for the XBeach input. The application of the model to the hindcasting of typhoons Maemi and Neoguri at Haeundae Beach in Korea shows satisfactory beach variations. Moreover, through sensitivity tests, we find that a wave height of 2 m behaves as a threshold value in the beach environment. Since the coupled model can be easily extended for real-time simulation, it can be employed in an early-warning system to provide beach safety.

Cho, M.; Shin, S.; Yoon, H.-D., and Cox, D.T., 2017. Numerical simulation of tsunami force acting on vertical walls. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 289–293. Coconut Creek (Florida), ISSN 0749-0208.

A tsunami can cause enormous loss of life and property in coastal communities. Therefore, when designing coastal infrastructures for protection against a tsunami, estimation of the tsunami force on a vertical wall is necessary. This work investigates the tsunami force on a vertical wall for different wave (tsunami) heights and cross-shore locations of vertical walls by using hydrodynamic numerical model simulations. The numerical model is based on the Reynolds-averaged Navier–Stokes equation, k-epsilon turbulent closure, and volume of fluid method to simulate the hydrodynamic forces induced by a tsunami. First, the numerical model was validated using physical modeling data from a large-scale laboratory experiment by comparing hydrodynamic parameters. Then, the numerical simulations were repeated for combinations of five wave heights and 28 cross-shore locations of vertical walls. For fixed cross-shore locations, the tsunami force increased in proportion to the wave height. For constant wave heights, the tsunami force exponentially decreased as the distance of the vertical wall from the shore increased. Finally, a predictive formula of the tsunami force on a vertical wall was proposed in terms of wave heights and the cross-shore locations of vertical walls based on a regression analysis for the numerical simulation results.

Liang, B.; Ma, S.; Pan, X., and Lee, D.Y., 2017. Numerical modelling of wave run-up with interaction between wave and dolosse breakwater. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 294–298. Coconut Creek (Florida), ISSN 0749-0208.

Breakwaters play an important role in coastal disaster prevention and mitigation. In this study, a numerical modelling of the wave run-up on dolosse breakwater is set up by integrating the CAD software SolidWorks and the CFD software FLOW-3D. The breakwater is built with the lower porous media and the upper armour blocks (dolosse), which is different from the current approach that treats the whole rubble mound breakwater as porous media. The numerical wave flume has been validated by analytic solutions of Stokes wave theory. The computational results are in good agreement with the empirical formulas under different wave conditions. The model was then used to calculate the wave run-up over movable dolosse breakwater, immovable dolosse breakwater and porous media breakwater under various wave conditions. The comparison results show that the porous media model can not sufficiently reflect the real world. And the displacements of the dolosse will affect the energy dissipation and lead to smaller wave run-up. It suggests that the interaction between waves and the dolosse breakwater is important for the safety of the breakwater. Therefore, the presented numerical study provides a more reliable approach for simulating wave run-up on dolosse breakwater that can provide support for the design stage of breakwater.

Chen, Y.; Xu, Z., and Lee, D.-Y., 2017. Numerical test on the impacts of submerged breakwaters for different design parameters. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 299–303. Coconut Creek (Florida), ISSN 0749-0208.

With the improvement of the living standards, the recreational use of the beach is gradually valued in China. There was a need of the development of artificial beach to meet the need of increased recreational use of the beach. Submerged breakwaters (SBW) is a widely used coastal protection measure, especially for the beach for tourist and water sports, which is constructed to reduce the wave condition to a required level to protect the beach from erosion and also to increase the recreational value of the beach. Understanding the impacts of the SBW on the transformation of the waves and the circulation induced by wave setup behind the SBW is important both for the proper design of the SBW for the protection of beach from erosion and also for water safety for the people enjoying water sports at artificial beach. There are so many design parameters including the dimensions of the SBW and wave conditions that impact the performance of the SBW. During carrying out a beach restoration project in China, it was recognized that there is a strong demand for the efficient method that the engineers can use in designing the SBW to predict the response of the SBW for different design parameters considering the detailed wave-structure interaction. An intensive numerical experiment had been carried out using wave resolving model for the evaluation of the impacts of the SBW on the wave transformation behind the SBW and also to develop an efficient tool to predict the wave tramsmission coefficients for various SBW design parameters. The development of such tool using intensive numerical experiment is discussed in this paper.

Kim, I.H.; Kim, J.; Jeong, Y.-M.; Hur, D.S., and Shin, S., 2017. Field observation and numerical modelling on the hydrodynamics behind a submerged breakwater. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 304–308. Coconut Creek (Florida), ISSN 0749-0208.

In 2014, a submerged breakwater installed near the erosion hot spot and the beach is being formed to salient beach behind the structure at Anmok beach, which is located on the east coast of Korea. The field monitoring has been carried out for past three years in order to investigate the change of beach morphology and shoreline before and after the breakwater construction. Wave gages were installed in the offshore location, in front of the breakwater and in the behind of the breakwater to investigate the wave height variation. A three-dimensional numerical model based on the Navier-Stokes equation with a Large Eddy Simulation (LES) turbulence closure scheme (LES-WASS-3D) was employed to predict the hydrodynamics near the submerged breakwater. The model used the beach topography and the bottom bathymetry before the breakwater construction to predict the wave transformation, refraction and diffraction due to the installation of the breakwater. The model simulated the wave and nearshore current fields especially behind the submerged breakwater and successfully predicted the wave heights near the submerged breakwater in high correlation (r² = 0.98) with the filed observation results. The numerical results also showed that the predicted wave and current fields could induce the sediment deposition behind the structure.

Kim, J.O. and Lee, J.K, 2017. UAV application for process control of the reclamation project. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 309–313. Coconut Creek (Florida), ISSN 0749-0208.

It is essential to acquire an accurate topographic information to efficiently operate a reclamation project. However, the measurement of large-size reclaimed land using terrestrial survey methods, such as total station and GPS requires huge number of efforts in terms of time and labor spending. Moreover, the coastal surveying that should be remote and hard to reach is extremely dangerous and sometime impossible. Therefore, in this investigation, UAV (Unammaned Aerail Vehicle) which has been actively considering in the field of spatial information currently, was applied for the construction management of reclamation project. In this paper, the feature matching and SfM (Structure from Motion) algorithm were used as image correction and matching technology. The UAV images were used to create three dimensional point clouds. The points clouds are transformed and aligned to global coordinate by using 21 GCPs (Ground Control Points) which are previously measured by terrestrial surveying. The aligned point clouds were eventually used to generate a DEM (Digital Elevation Model) and ortho-imagery. This study also assessed the positioning accuracy of the results by comparing with terrestrial surveying results using total stations at 426 check points on the study area. The RMSE (Root Mean Square Error) of positioning differences between the coordinates of UAV photogrammetry and terrestrial surveying was within tolerance, 4.8 cm, except for the results at non-ground points. This paper, consequently, presented an availability of the UAV for the photogrammetry, so that it can be fully expected the UAV photogrammetry could be applied in many fields included construction application.

Kwon, M.; Jun, K.S., and Kim, T.-W., 2017. Evaluation of probabilistic storage prediction model (PSPM) for optimal reservoir operation during a drought. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 314–318. Coconut Creek (Florida), ISSN 0749-0208.

The Probabilistic Storage Prediction Model (PSPM) is a model that probabilistically predicts the future reservoir storages considering the uncertainty of natural inflow. This study simulated reservoir operation using the PSPM and evaluated the usefulness of the PSPM compared to the actual reservoir operation during the recent severe drought of the Chungju Dam basin in South Korea. The initial storage was set to observed storage at the end of January 2015, and the reservoir operation for achieving target storage at the end of June was simulated for various achievement probabilities. The differences between the simulated storages and the actual storage at the end of June 2015 was as large as 14–20% of effective storage capacity of the reservoir. The maximum supply reduction for achieving target storage simulated for the achievement probability of 0.8 was less than actual maximum supply reduction. This is possible by storing more water in advance to prepare for more severe drought. PSPM can offer valuable information as a decision-making tool, which will enable reservoir managers to secure water in advance, and thus mitigate severe drought damages.

Roh, J.Y.; Shin, M.S.; Suh, Y.C.; Yang, I.T., and Lee, D.H., 2017. Evaluation of nautical chart adequacy in the coastal area around Incheon Bay using satellite imagery with AIS data. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 319–323. Coconut Creek (Florida), ISSN 0749-0208.

The Nautical Chart (NC) is an essential tool for marine navigation that depicts the configuration of the shoreline and seafloor, such as bathymetry, locations of dangers to navigation, locations and characteristics of aids for navigation, anchorages, and other features. These features could be continuously changed according to the nature of a waterway and human activities. Hence, using the old or uncorrected NC for navigation is strongly prohibited. Moreover, the adequacy of NC is a must for the safety of the seaway before navigation. The general manner of ensuring the adequacy of NC is to access the change in bathymetry along with the vessel traffic information in seaway. The recent bathymetry update is commonly done by using hydrographic surveying techniques, such as Multi-Beam Echo Sounder (MBES) and Airborne LiDAR Bathymetry (ALB). These techniques provide both highly accurate and a dense coverage of depth measurements. However, high cost and logistic challenges are required. This study applied the satellite-derived bathymetry from Landsat imagery with Auto Identification System (AIS) data as vessel traffic information to evaluate the adequacy and completeness of NC information in the coastal area around Incheon Bay, Korea. Based on satellite data, submarine topography was derived and found to be very highly correlated up to 10m depth. The procedure can easily identify the changes of bathymetric information in NC and could be an effective and economic way of ensuring the NC adequacy without MBES or ALB surveying in the coastal area of Korea.

Lee, D.H.; Acharya, T.D., and Lee, H.S., 2017. Evaluation of seabed classification using hyperspectral data around the coastal area of Geoje Island, Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 324–328. Coconut Creek (Florida), ISSN 0749-0208.

Seabed classification is an important part of current coastal research because it characterizes the seabed and its habitats. Seabed characterization makes the link between the classified area and the physical, geological, chemical or biological properties of seabed. This paper addresses the possibilities of the use of the hyperspectral data obtained from a CASI-1500 airborne sensor to map the seabed covers around the coastal area of Geoje Island, Korea. After radiometric, geometric and atmospheric correction for the raw hyperspectral data, the classification was performed in three steps. Firstly, thirteen classes of seabed were identified using an unsupervised spectral angle mapping algorithm in combination with data collected by ground survey. Secondly, seabed mapping was performed for each class separately. Finally, an accuracy assessment of the seabed mapping results was performed using data from ground survey. The overall accuracy was 84.29% with a kappa coefficient of 0.828. The results indicated that the hyperspectral data can help not only to classify the seabed material remotely and precisely, but also to construct the continuous geographical information for an effective management and conservation of the coastal area in Korea.

Jeon, H.S.; Obana, M.; Kim, K.H., and Tsujimoto, T., 2017. Flow and sediment transport with non-submerged riparian vegetation in 1D scheme. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 329–333. Coconut Creek (Florida), ISSN 0749-0208.

Recently depth averaged analysis has become popular and powerful even in a stream with vegetation by taking account of form drag due to vegetation. A number of studies about the drag force related with various vegetation configuration were also carried out and focus on determining the drag coefficients and empirical formulas. However, there must be some restriction for application in depth averaged model for flow with vegetation. When it is applied to a stream with vegetation, form drag due to vegetation is taken into account, but the shear stress is not properly described because the frictional resistance law due to bed roughness is not modified in vegetated area. Therefore, friction factor in depth-averaged scheme must be modified by the flow with vegetation. In this paper, the concept of “bed roughness boundary layer” is proposed and analytically formulated against the vegetation density. Sensitivity analysis were also conducted under several parameters and vegetation densities. The calculated results bring the reasonable evaluation of shear stress and proposed concept will affect other many kinds aspect in fluvial process, which will be clarified successively. Resultantly we are able to apply the depth-averaged analysis reasonably to flow and fluvial process in a stream with various density of vegetation.

Son, S.; Kim, J.; Yoon, H.-D.; Jung, T.-H.; Do, K., and Shin, S., 2017. An observational and numerical study of storm-induced morphologic changes at Sanpo Beach, Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 334–338. Coconut Creek (Florida), ISSN 0749-0208.

This study was conducted to investigate morphological changes at Sanpo Beach due to the storm through field observation and numerical simulation. Sanpo Beach located on the southeast coast of Korea had been significantly affected by typhoon Goni while some changes in beach profile was expected due to the strong storm-induced currents. Series of field observations on the beach topography, bottom bathymetries, shorelines, sand samples, and incident waves were carried out in order to investigate the morphological changes at Sanpo Beach during the typhoon season. In particular, Real Time Kinematic-Global Positioning System (RTK-GPS) and single-beam echo-sounder were deployed to collect beach topography and bottom bathymetry data, respectively. Observational results represented spatial and temporal changes of shoreline and sand bars during a storm event. For more close look at the process of morphologic changes derived by the sediment transport mechanism, field-scale numerical simulations were performed in parallel using Xbeach. Xbeach is one of the widely-used, open-source models which calculate sediment transports and morphologic changes by hydrodynamic processes of short (and/or long) waves, wave-induced setup and unsteady currents. Bathymetric evolutions, as well as shoreline changes predicted by the numerical results, revealed good agreements with observational data.

Kim, H.-J.; Suh, S.-W.; Seok, J.-S., and Park, W.-K., 2017. Sedimentation for a flood-dominant estuarine harbor induced by anthropogenic activities. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 339–343. Coconut Creek (Florida), ISSN 0749-0208.

Sedimentation around the Kunjang harbor area in Korea has intensified at a rate of ~2.0 m/yr because of the construction of an estuarine dam in 1988, which resulted in the tidal energy being blocked and the development of a flood-dominant environment. The construction of several harbor facilities cumulatively altered the tidal hydrodynamics and yielded sedimentation. Moreover, the annual maintenance dredging for the main channel accelerated alteration. In order to understand the sedimentation characteristics, archived intensive depth measurements were used to assess the variations in the bottom shear stress. Our results showed that the bottom shear stress and tidal prism have lessened. The resulting sedimentation should be managed through dredging or minimization plans based on an appropriate engineering solution. In this paper, we suggest an optimized weighting factor to represent diverse physical morphological variations that affect the shear stress. It can be used to compensate for unsatisfactory results generated by a morphological model. Our findings can help in devising an efficient engineering approach to mitigate sedimentation for a flood-dominant estuarine harbor.

Kim, H.J.; Park, W.K., and Cho, W.C., 2017. Analysis of coastal erosion in Sanpo-Ri, Uljin-Gun (South Korea) using field survey and measurement data. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 344–348. Coconut Creek (Florida), ISSN 0749-0208.

Several parts of the coastal road in Sanpo-Ri, Uljin-Gun, located in the eastern part of South Korea, have subsided due to erosion and scouring at the bottom of the front face of revetments, caused by frequent high wave attacks. In this study, we carried out field surveys and measurements (including waves, current, water depth, seabed material, beach profile, and shoreline) along the Sanpo-Ri coast and in Namdae-River and Wangpi-River, located in the northern part of Sanpo-Ri, in the summer and winter seasons, in order to analyze and determine the erosion process along the Sanpo-Ri coast. In addition, we used 8 aerial photographs, taken from 1988 to 2013, to analyze long-term coastline changes. The erosion of Sanpo-Ri coast was initiated and progressed not only due to the decreased width of the beach by the construction of coastal roads and the increase of reflected waves at vertical revetments, but also due to the 35 small dams installed in Namdae-River and Wangpi-River since 2000 that have interrupted the sand transport from the rivers to the coast. We performed numerical analyses on the generation of the long-shore current, sand transport, and shoreline change based on field data, and analyzed the erosion process along the Sanpo-Ri coast. These numerical monitoring data and results will be useful to establish coastline maintenance and protection plans on the Sanpoi-Ri coast and on other coasts with erosion problems.

Kim, G.H.; Jho, M.H., and Yoon, S.B., 2017. Improving the performance of SWAN modelling to simulate diffraction of waves behind structures. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 349–353. Coconut Creek (Florida), ISSN 0749-0208.

Phase-decoupled wave models such as SWAN model cannot in general deal with the diffraction of waves behind coastal structures or islands. Improvements have been made recently to the SWAN model by including the diffraction effect that allow energy transfer between the directional spectral components. For a successful simulation of the diffraction problem the grid size should be smaller than 1/10 of the wave length. However, this limitation on the grid size seems to be unrealistic to cover a large computational domain, and a practical way to deal with the diffraction problem for the case of large grid size is indispensable. The tests of the performance of the SWAN model for the diffraction of monochromatic waves with various grid sizes show that the diffraction effect disappears behind a breakwater when the grid size increases. To improve the model performance the directional turning rate given by the SWAN model is artificially increased by increasing the diffraction parameter. To test the performance of the modified SWAN model a simple case of monochromatic wave incident on a semi-infinite breakwater in a water of constant depth is considered. As a result, the diffraction effect appears in a shadow zone even for the case of large grid size. The appropriate amplification factor for the diffraction parameter is found by trial and error for a given grid resolution, and an empirical formula for amplification factor is obtained. A practical way to improve wave diffraction effect for the case of large grid size in SWAN is proposed.

Choi, Y.-K. and Seo, S.-N., 2017. Shock capturing shallow water model for long waves generated by a moving atmospheric pressure. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 354–358. Coconut Creek (Florida), ISSN 0749-0208.

The shock capturing numerical model based on nonlinear shallow water equations is developed to predict run-up as well as edge waves generated by a moving atmospheric pressure disturbance across a straight shoreline on a sloping beach. The HLL approximate Riemann solver with the fifth order accurate WENO scheme is used to compute numerical flux in spatial discretization, which yields better results in comparison with TVD-MUSCL type schemes. Numerical experiments are conducted for wave propagation by a moving atmospheric pressure disturbance normally approaching the coastline. When the atmospheric pressure disturbance suddenly acts on the water surface, both free and forced waves are generated and amplified due to shoaling and Proudman resonance. The maximum run-up is presented using different moving speeds for an atmospheric pressure. While wave run-up and run-down are repeated at the shoreline, edge waves are generated and propagate in the alongshore direction due to wave refraction.